What is the Difference Between Waterfall and Spiral Model?

The Waterfall and Spiral models are both used in software development, but they differ in their approach, flexibility, and risk management. Here are the main differences between the two models:

1. Sequential vs. Evolutionary: The Waterfall model follows a sequential method, while the Spiral model follows an evolutionary approach.
2. Risk Management: The Waterfall model identifies and rectifies errors and risks after the completion of stages, while the Spiral model identifies and rectifies them earlier in the process.
3. Customer vs. Developer Focus: The Waterfall model is generally used by customers, while the Spiral model is adopted by developers.
4. Project Size: The Waterfall model is best suited for small projects with clear goals, while the Spiral model is better for large projects.
5. Flexibility: The Waterfall model is inflexible and difficult to change, while the Spiral model is flexible and allows for easy changes.
6. Risk Level: The Waterfall model involves a higher amount of risk compared to the Spiral model.
7. Cost: The Waterfall model is generally less expensive than the Spiral model.

In summary, the Waterfall model is a linear, sequential approach to software development that is best suited for small projects with clear goals. It is generally used by customers and involves a higher level of risk. On the other hand, the Spiral model is an evolutionary approach that is more flexible and better suited for large projects. It is adopted by developers and involves a lower level of risk.

Comparative Table: Waterfall vs Spiral Model

Here is a table comparing the differences between the Waterfall and Spiral models:

The Waterfall model follows a sequential method and is generally used by customers, while the Spiral model works in an evolutionary method and is adopted by developers. The Spiral model is more flexible and less risky compared to the Waterfall model, but it is also more expensive.